15-463 Project 3: Photo Mosaics

Photo Mosaics
Stephen Lin
sl2a@andrew
10/25/2006

WARNING: LOTS OF LAGE IMAGES. IT'S GONNA BE SLOW

Image Rectification

The first set of images are for image rectification. Both images were taken in Wean Hall.
All images were resized to a width of 640px to fit on the screen. Click them for the full sized versions.

Image of a whole bunch of monitors, original size 1124x958. Rectified so that you were looking at the pair of monitors on the rack (the center of the picture, right monitor has a sticker) head on. Used the 4 corners of the rack around the 2 monitors as control points. The control points were rectified to the a rectangle with the same upper left coordinate and left-height of the rack, and a height:width ratio of 1:2. One interesting note about this picture is that the original version had points to the rigth of the vanishing point, thus resembling something beyond 180 degrees of what the viewplane would be. This resulted in some very very large images with weird results. As a result, I cropped out the image beyond the vanishing point before feeding it into the homography.
This image has been resized and cropped to fit on the screen. To see the raw, uncropped image, click here (warning, big PNG)

The next image is of one of the whiteboards next to the elevators, original size 1280x958px. The control points are the 4 corners of one of the panels (2nd most to the right panel). This was rectified to a rectangle with the same upper left and bottom right corners.
Once again, this image was resized and cropped to fit the screen better. Click here for the full humongous image.

Now onto the good stuff

The mosaic image is taken from the 4th of July 2004 in Boston. Originally a set of 13 images, I figured it was too much work for my computer to handle, and instead, limited it to the 3 center images. In these images, you can see the T barge in the river that they launch the fireworks off as well as some notable buildings. This uses a linear cross-blend along x-coord in areas of overlap.
Original images:

The mosaic:

Bells and Whistles #1

Adding some chalk drawing to the cut. Put the CMU EMS patch as a chalk drawing on the sidewalk. In making the mask, I added some texture to try to make it seem more chalky, but because of the angle, it's not very apparent.
Original images:

The result:

Bells and Whistles #2

When I was still in highschool, there was a big vote to allow the increase of the property tax in my hometown. At that time, I was taking photos for my school newspaper, and I was assigned the job to get photos of people holding signs encouraging people to vote "yes" or "no", these two pictures being the ones we used in the newspaper. Both sides claimed it would make Newton stronger and safer, and frankly, I don't think they really knew. So would anyone notice if I changed the signs a bit?
Original pictures:

And the ol' Switcheroo:

Bells and Whistles #3

These two pictures were taken while I was visiting Taiwan. I think I may actually have been trying to get pictures to compare the difference between night and day of the view out the window. A linear blend gradient goes along the x-axis over the overlapping areas
Original Images:

Result:

Bells and Whistles #4

Another cute use of the fuctions that I created for this project. Looking through the photo archives, I came across two pictures, one of the fire station down the street from my house, and the Gate at the entrance to Chinatown, Boston. This basically just adds the gate to the firehouse. However, the lack of foresight lead to a rather odd picture. First, the picture of the gate is taken at a different angle than that of the fire house. Second, the fake "gate" at the firehouse would be 2d, while the gate in Chinatown was 3D, and finally, the lighting difference really makes the image look... odd.
Original Images:

Result:

Notes